My opinion is "yes" - the source is available and runs as a docker container, the client setup is pretty trivial (on Android you'll need Fennec or another alternate build of Firefox to get at the settings). I'm aware of one user group running a shared instance and it seems to work as advertised.
So I click your link, but the repo says
> Note that this repository is no longer being maintained. Use this at your own risk, and with the understanding that it is not being maintained, work is being done on its replacement, and that no support or assistance will be offered.
So I guess I'll have to wait a little more...
So basically they stopped running the older version themselves but don't consider the newer version production-ready yet. What a mess.
Though when I log in on a mobile device I don't even have to enter the password so I kinda doubt it passes the mud puddle test.
But at least the info is not just stored in the clear ready for datamining like Chrome or Edge do. Though Chrome has very recently added e2e for its passwords but not for the bookmarks.
I didn't look into it personally but a few years ago I tasked an employee with setting up local instance of this for a very privacy conscious small business and after a few days of looking at it he said that it would be too much work to get the released material into a state that end users could make use of.
This could have changed since then however.
Yes. See my comment above. Nothing that a persistent admin can't pull off. I wouldn't blame your coworker for giving up, though.